Recent studies have shown that B cell production is significantly reduced in the bone marrow of aged mice and humans [48], Frasca et al. found that aging downregulates B cell type switching in humans and mice [49]; in addition, hypercholesterolemia Apoe-/- mice and low-density lipoprotein-deficient mice have also shown that protective immunity of B cells can delay the progression of atherosclerosis, while the lack of B cells increases the occurrence of atherosclerosis [50, 51]. The gene discussed is APOE; the disease is atherosclerosis.